Automaic



Feb. 12 1924. 1,483,438

F. H. H'EDIN AUTOMATIC RECLOSING CIRCUIT BREAKER SYSTEM Filed Oct. 25, 1922 Oil/WENT TH/PU TUBE- CA 779005 CURHENZ' Inventor-d FF ed H-Hedin,

His Actor-neg.

Patented Feb. 12, 1924.

UNITED I STATES P TE OFFICE FRED H. HEDIN, or coNNEcrrou'T, Assrcnon 'ro GENERAL ELECTRIC comrANY, AcosronArIoN or NEW gomr.

An-roMA'rrc .nEoLosriTG-orncorr-nnEAK R SYSTEM.

Application" filed October 25; "1922 S'e'r i al no; 'sseis'ra,

" To allwhom'it may concern:

'B'e it known that I; FRED H. HEDIN, a citizen of the United States, residing at Willimantis; in the county of Windham, State of @onnecticutg have invented certain new and useful Improvements in"Autoniatic Reclosingig-Circa]it-Bieak'er Systems, of which the blinding is a; specification. My-"i ngention relates to automatic reclosl in'g'circul flbreakersystems and particularly to suchsystems in -which the'reclbsing ofa 'circuit 'breaker which connects a source of currents.ancadeircuit, is c ontrol led by an electron discharge tube which is arranged to IE connected? when t'he"cirduit breaker is open, that the current through the tube variesfn-;accordance"with the load resist- .alnbe: "-'*On obj ectof my invention isto-pi'oyide a ife'iii and iniprovediarrangement of connecsense-f an electron discharge tube, whereby Variations 'infthe Voltage ofthe source, which istofbeconnected t o-"th load-"ircdifiby the of thefcircuiflbreaker'," have subjs't'anti ally no efi'ect'upon 'the value of load esistafic ieduiredr t6"'rec1ose"'the' circuit breaker.

' My invention will be better understood fron'i' the "following description, taken 'in connection with the accorn' ia'nying drawing, and its scopewill be nointed out in the appended claims.

In the accompanying drawing, Fig. 1 is a diagram of an automatic reclosing circuit breaker system, embodying my invention, -and Fig. 2 shows a characteristic curve of an electron discharge tube, which may be enr p oye "Referring to Fig. 1 of the drawing, 1 represents a circuit breaker which is arranged to connect a source otcurrent 2, shown as a-direct' current generator; to a loadcircuit v3 to which 'is connected'the load 'R,,'. The circuit breaker 1 which may be of any suitable type, is shown-as comprising a closing rcoil 5 which when energized. closes and maintains'thc circuit breaker in itsclosed position; The coil 5 is arranged to be connected to any :suitabIe source of current, such as the generator 2. When the circuit breaker 1 is closed, 'the circuit of the coil 5 includes the contacts 66f an overload relay 7 and the'anxiliai'y contacts 8 on the circuit breaker l; which are closed when the "circuit breaker is closed." 'When the circuit open its contacts-'16 on'ly'iwhenrthe oad cur:- -rent exceeds aipredeter'mined-walue.

' When the bircuit lbreakerzliisopenfa 01117- .rent limiting means-{sachets rtwolre'si'stors -R i and NR is :conn'ectedi iinqseriesr: with; a load B so asto' lin'iit 'the'currentsnppliedto the load. 'aThese resistors are short-circuited by the circuit 'breakerivi'lien it'zisrcloseil'.

breaker 1 is ope'nethe 'circuit'of theic'oilifi is arranged to be completed: through-ithe'cco'ntactsr fi of the-overload relay 7rand:th'e :con tactsll of a reclosing; relayarl2g the .coilrl'3 of'which is arrangedto be' energized in as.- 60 cordance with the zload'resi'stahceivinia mam- Tier: hereinafter 1 described."

: The OVOi'lOfidIBlflijlifIi'iSi 'rovided'awith an operating winding-151 whic iis iconnecbed to the load acirc'i1its3 any suitable: mahnenso that the current through'ithezboilllaisi no pbrtional toithecurrent supplied; wither cad circuit when'the circuihbreaken d iszicldsed. The relays? is $80 designedithat'itp crates to -17 is energized. by" the closing: of the. contacts 16. The'closi'ng of the contacts:l9 of the relay 18 connects the- IBSlSbdI'SrR and R which are-connected in series with each other; in parallel with the ldadwresistanoe R and the resistor R so ,as' to form a Wheatstone bridge. The cathode 23 of an electron discharge tube 2 i-is connected to a point between the resistors R and R As shown in the drawing, the cathode 23 is connected in series with'resist'orsR and'R so that the current through the resistors heats the cathode. The tube 24 is also provided with an anode or plate 25 which -is"'connected to one end of the coil-13 of'the-reclosing relay l2, the other end of the coil being connected to the positive terminals of the generator 2 so that theplate'25 is more positive than thecathode 23: The tube 24 is also provided with any suitable means for varying the current through it such-as a grid 26 which is connected to a point between the resistor R and the load 2B," The resistors R and R, and the resistor R which forms one arm of the Wheatstoue bridge, are preferably of such values that with a given generator voltage, when the circuit breaker I is opened, the potential difference between the points to which the cathode and the grid are connected is zero when the load resistance R, is a value at which it is desired to reclose the circuit breaker, and when the load resistance is less than this predetermined value the point to which the grid is connected is morenegative than the point to which the cathode is connected, and when the load resistance is greater than this predetermined value the point to which the grid is connected is more positive than the point to which the cathode is connected. Preferably, the relay 13 is so designed that it will operate in response to the value of the current that flows through the tube 24 when the potential difierence be tween the points to which the grid and the cathode are connected is zero. In order, however, to obtain sufiicient current through the tube to. operate the relay 13 under the above conditions a battery 20 may be connected in series with the grid so that the potential of the grid is more positive than the cathode although the. potential difference between? the two points of 'the' Wheatstone bridge,'towhich the cathode and grid are connected; is zero. 'lVitlI such an arrangenient', it 7 is evident that variations in" 7 the i-voltage "of: the source 2, when the circuit breaker is open, has? no efiect upon the value of load: resistance required. to make the potentiakdifierence. betweeni the-:fpoints to which'i-the cathodc and the grid-are: connected ZGIOs V Inorder 'tocompensate for variations in the clirrent through the tube, due to changes in the temperature of the cathode prod'uc'ed byyariations in the voltage ofthe source it is preferable to operate the tubeion the substantially flat portion A--B of the character- 'lstic curveshown in Fig 2, so that within certain limits, wide'variations in the filament temperature produce= very small changes in the current through the tube;

' The operation of the system shown" in Fig. 1 is as follows:

Uiider normal operating conditions, the

contacts 6 of the'overload relay 7 are closed arid'the'circuit breake'rl is held in its closed position-Ib'y' the energization ot the coil 5, thescircuit ofwhic'h includes the contacts tiiofithe overload relay 7 and the auxiliary contacts' 8 on thecircuit breaker. auifiliary' contacts=16 on the circuit breaker Since the 1' 'are 'open'; the "time relay 18 is not en- 'ergizedi The contacts 19' therefore are open,

so u'that the circuit through the resistors ligand-R, and the cathode 23-is-open. Gonsequently', there 15 no current through the tribe-24 and the coil '13=n-F the recl'osing relay 1?.

When an overload or a short-circuit occurs on the load circuit, overload relay 7 opens its contacts 6 so that the coil 5 is deenergized and the'circuit breaker 1 opens.- The opening of the circuit breaker 1 removes the short-circuit from around the resistors R and R,, so that they are connected in series with the load circuit to limit the current supplied thereto. After the circuit, breaker opens, the current through the coil L-l of the overload relay 7 decreases, so that the relay closes its contacts 6.

The closing of the auxiliary contacts 16 on the circuit breaker 1. when it opens, completes the circuit of the coil. 17 of the time relay 18. After a predetermined time, the relay 18 closes its contacts-19, thereby completing the circuit through the resistors R, and R and the cathode 23 of the electron discharge tube 24. The cathode 23 heats up and current flows through the tube 24 and the coil'13 of the reclosing relay 12. With a short-circuit or an overload connected tothe load circuit, the current through the coil 13.is not suflicient to-cause therelay 12'- to close its contacts 11. As -the load resistance increases, the potential of, the grid 26 becomes more positivewith respect to the cathode 23,- so that the; current through the tube -andthe coil; 13, increases. When the load iresistancel reaches a :predetermined value so that the potential difierence between. pointsto which the cathode and the grid are connectedjsa eten- That I claim as new and-desire tosecure by Letters Patent! ofthe United States, is 1-9- 1'. In anautomatic=-' reclosingt circuit breaker system," a: source'of'curi-ent, a l'o'ad circuit, 'a: circuit breaker fon connecting said sou'roe to said circuit, an electron 'discharge tube having its anodqcathode and grid connected to sai'dsystemso that the andion

potential difference" between the points to which the grid and the cathode are connected is zero when the' load resistance is a predetermined value, and means responsive to the current'through said tube for causing the closing ofsaid circuit breaker when the potential clill'erence between the points to which said grid and cathode are connected is a predetermined value.

2. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said circuit, an electron discharge tube having its anode, cathode and grid connected to said system so that the potential difl'erence between the points to which the grid and the cathode are connectedis zero when the load-resistance is a predetermined value, and means responsire to th current throu h said tube for causing the closing of sai circuit breaker when the potential difi'erence between the points to which'said grid and cathode are connected is zero.

3. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said load circuit, a resistor arranged to be connected in series with said source and said load circuit when said circuit breaker is open, a second and third resistor arranged to be connected in series with each other and in parallel with the circuit comprising said first mentioned resistor and said load circuit so as to form a Wheatstone bridge, an electron discharge tube having its cathode connected to a point between said secondand third resistors, its grid connected to a point on said first mentioned resistor and its anode connected so as to be more positive than said cathode, said resistors and the connections of said tubes being such that the potential difference between the oints to which said grid and said catho e are connected is zero when the load resistance is a predetermined value, and means responsive to the current through said tube for causing the closing of said circuit breaker when the potential difierence between the points to which said grid and cathode are connected is a predetermined value.

4.In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said load circuit, a resistor arranged to be connected in series with said source and said load circuit when said circuit breaker is open, a second and third resistor arranged to be connected in series with each other and in parallel with the circuit comprising said first mentioned resistor and said load circuit so as to form a heatstone bridge, means operative after said circuit breaker has been open for a certain length of time to effect the connection of said second and third resistors in parallel with the circuit comprising said first resistor and said load circuit, an electron discharge tube having its cathode connected in. series with and at a point between said second and third resistors, its grid con nccted to a point on said first mentioned resistor and its anode connected so as to be more positive than said cathode, said resistors and the connections of said tubes bcin z such that the potential difference between the points to which said grid and said cathode are connected is zero when the load resistance is a predetermined value, and means responsive to the current through said tube when the potential difference between the points to which said grid and cathode are connected is zero for eii'ecting the closing of said circuit breaker.

An automatic reclosing circuit breaker system comprising a circuit breaker for connecting a source of current to a load circuit, an electron discharge tube comprising a cathode, anode and grid connected so that the potential between said grid and cathode varies with the load resistanc in such a. manner that the current through the tube increases as the load resistance increases, and means responsive to the current through said tube for controlling the operation of said circuit breaker, characterized by the fact that said tube is so connected that said last mentioned means operates to cause the closing of said circuit breaker when the potential difference between the points to which said grid and cathode are connected is zero.

6. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said load circuit, a plurality of resistors arranged to be connected to said source and said load circuit when said circuit breaker is open so as to form together with the load resistance a Wheatstone bridge, an electron discharge tube having an anode, a cathode and means for controlling the current through said tube connected and arranged so that the current throu h the tube is dependent upon the potentia difierence between two points on said Wheatstone bridge which varies with the load resistance, and means responsive to the current through said tube for causing the closing of said circuit breaker when the potential difl'erence between said two points on said Wheatstone bridge is a predetermined value. 1

7. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said load circuit, a resistor arranged to be connected in series with said source and said load circuit when said circuit breaker is open, a second and third resistor arranged to be connected in series with each other and in parallel with the circuit comprising said first mentioned resistor and said load circuit so as to form a VVheatstone bridge, an electron discharge tube, having an anode, a cathode and means for controlling the current through said tube connected and arranged so that the current through the tube is dependent upon the potential difference between two points on said VVheatstone bridge which varies with the load resistance, and means responsive to the current through said tube for causing the closing of Said circuit breaker when the potential difference between two points onsaid VVheatstone bridge is: a predetermined value.

8. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said load circuit, a resistor arranged to be connected in series with said source and said load circuit whensaid circuit breaker is open; resistor arranged to with each other and in parallel with the circuit comprising said first mentioned re sister. and said loadcircuit so' asLto forin a second andithirdl be connected in series.

a Wheatstone bridge, means operative after said circuit breaker has been opened for a certain le h of time to efl'ect the connection of said second and third resistors in parallel with the circuit comprising said first resistor and said'loadcircuit, an electron discharge tube having an anode, a cathode and means for controlling current through saidtube connected and'alrranged so that, the 'current through 'thetube'is dependent. upon; the potential difference between .two points onsaid' Wheatstone bridge which varies withjthe load resistance, and means responsive to the current through said tubejjor' causing the closing of said circuit breaker when'the potential difierence between two points onsaid- Wheatstone bridge is zero.- I

In witness whereof, I have hereunto set my hand. this 18th-dayof October 1922.

- i FRED H; HEB-IN; 

